Leaky fuel tank.... crap!

[Kirk Feldkamp]

Anyone have any ideas for sealing a welded aluminum fuel tank after it has already been made? I think I have a few pinholes. Damnit!

-Kirk

[Kirk Feldkamp]

Anyone have any ideas for sealing a welded aluminum fuel tank after it has already been made? I think I have a few pinholes. Damnit!

-Kirk

[Frank]

do a "dye-penentrant test" (red and white) before hand

emtpy it
fill with thinners
empty it

leave overnight with a heater blowing warm air over it

it should now be ok to weld

even if it does have foam in it...

a few quick spots wont ruin all the foam

Frank

[The guru of guru's]

make another tank

[Dan Deussen @ Weber Motor]

Turbo-

Go to your local car parts store and ask for gas tank sealer. It is a kind of epoxy that you splash around in the empty tank and let cure for 24 to 48 hours. If you can't find it at you local store, let me know and I ask our gas tank guy for the exact name of the product. We used this stuff last year when we were running E85 in an Al tank to prevent corrosion.

[JonBoy]

let me rephrase that in normalspeak -

for a quick fix, there is a 2 part epoxy sealant (ie araldite) with a metallic filler that is sold to patch fuel tanks -

i dont know whether it would eventually vibrate loose or not but it seals pretty well.

[Farls]

As Dan said there is a specific sealant for petrol tanks, otherwise we have had success with petrol resistant silicon sealant.

[TA]

Carrol Smith reccomends Loctite 290 for sealing the welds in fuel (and other) tanks. Reference and technique (brush on to weld, wipe off excess with rag) on page 155 of "Engineer To Win".

No personal experience with it.

Good Luck, Ted

[MikeWaggoner at UW]

You may need to go to a motorcycle shop for gas tank liner. The stuff I used in my old bike was called cream, I think.

[Kirk Feldkamp]

Thanks for the advice guys. I'll see what I can find today.

-Kirk

[osubeaver]

We just tested our tanks yesterday and had the same problem (a few tiny holes). We were able to fix most with a weld and then used epoxy on the outside for the remaining few. It seems to be holding good so far. As for tank sealant, we used Kreem last year to protect from the E-85, and I think we will use it again this year. If anyone knows the names of any other products for sealing the inside of a tank (and where to buy them), I would appreciate it. Thanks.

[James Waltman]

KREEM - We bought some this weekend at one of the local motorcycle shops.
Find it online here http://motorcyclecity.com/Parts/tank-repair.htm

Eastwood sells something similar
http://www.eastwoodco.com/
search for gas tank sealer

Even more
http://www.prp-porshop.com/por-15-tank-sealer.htm
http://www.caswellplating.com/aids/epoxygas.htm

[Wizard]

We have used the Por-15 Tank Sealer (link above) after we finish welding our aluminum tank just to make sure there are not any leaks. Easy to use, it does take a long time to dry. I recommend having a fan blow the inside to speed up the process.

For a quick fix I recommed cold fusion welding or JB Weld as I like to call it. Works quick and easy and it you prep the tank correctly it lasts.

[-]

to back up the wizard... I have made made a tank or two with holes in them. When I did, I would take the safe route, and empty the tank, blow air through it for a bit (say five minutes to blow out the gasoline), carefully stike a match at the opening to burn off any vapor (there usually isn't any, this is just to make sure) then I go and weld up the spots where there are holes.

To avoid getting holes in the first place, when you are welding, when you come to a stop of a weld (where pin holes usually are) let off the welder slowly to allow for the pin hole to close and you will end up with a gasoline tight joint. This is assuming that you are tigging your tank together.

Good luck

[Gonzo]

I don't know if this tip is to obvious or not. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

But don't start a weld bead at the end of the previous one instead weld in the other direction and run back over the finish of the previous bead so that you fill up any pin holes.

Also helps if you cut the end of each bead out with a cutting disc on a small grinder. Just touch the weld to remove where the pin hole could be hiding but don't actually cut the parent material.

It would also pay to pressure test your fuel tank after welding so that you know it won't leak before you fill it. Just fill the tank with 3 psi of air and squirt the welds with dishwashing liquid and watch the bubbles.

[Micko..]

don't know if you know this or not, but i thought i'd mention it anyway.fuel tanks should be steamed and filled (not sealed) with inert gas before welding, it is easy for fuel vapors/residue to remain in the seams and when you weld them they expand to fill the tank and unexpected big bangs are bad http://fsae.com/groupee_common/emoticons/icon_mad.gif, and i'm a pussy.

[Kirk Feldkamp]

Found 2 tiny pinholes when I took a closer look at the tank today. Turns out they were from 2 tacks holding in the fuel box, and not actually from any of the tank seams. How's that for dumb luck?! Now to plug the holes...

-Kirk

[formula_geek]

On a lighter note...

Be sure to show your new members how to use a regulator before instructing them to put "5 or 10 lbs of air" in the new tank and submerging in water. Kettering's 2002 fuel tank had a strange concave bulge in each face after being pressure tested. Shop line pressure (approx. 125 psi) didn't do it any good!

(Sorry Stevie B., I couldn't resist)

[Gonzo]

Ouch!

People need to be more careful with air pressure. Although 125 psi isnt to bad.

Over the speedway season we witnessed a crewman (from another team) beading a tyre with a dive bottle unregulated! The tyre blew off the rim and flew about 25 metres in the air. The rim left a 1/2" groove in the asphalt and followed the tyre into the air getting about 15 metres high before both came back down narrowly missing some very surprised onlookers.

The crewman right arm was very badly broken and he is lucky not to have sustained more injury.

Be careful with air.

[osubeaver]

Holy crap!